Propagation Protocols for 10 Threatened Cornfield...

Propagation Protocol: Adonis annua L. of 58

Propagation Protocols for 10

Threatened Cornfield Annuals

Report for Colour in the Margins

Ted Chapman, Sarah Pocock & Rachael Davies

October 2018

of 58

Propagation Protocols for 10 Threatened Cornfield

Annuals

Report for Colour in the Margins

Ted Chapman1, Sarah Pocock1 & Rachael Davies2

October 2018

1 Conservation Science, Royal Botanic Gardens (RBG) Kew,

2 Collections, RBG Kew

Background

RBG Kew’s UK Native Seed Hub (UKNSH) was commissioned and funded by Colour in the Margins to develop

propagation protocols for ten cornfield annual species using existing Millennium Seed Bank (MSB) data

supplemented in some cases by new germination and propagation trials. Colour in the Margins is a Back

from the Brink project led by Plantlife.

All work was carried out by the UKNSH in the MSB and Wakehurst Plant Propagation and Conservation Unit.

Data relating to seed collection dates, weight, longevity, dormancy-alleviation and germination

requirements were sourced from the MSB’s Seed Bank Database, accessed between April and October

2018. Data relating to seedling establishment and growth were sourced from horticultural records held by

the UKNSH, accessed over the same period. References for all other sources of information are provided in

the text.

About the UK Native Seed Hub

The UK Native Seed Hub seeks to mobilise the seed collections, facilities, technical knowledge and scientific

expertise of RBG Kew to support conservation and habitat restoration in the UK.

We provide plants and seed, technical services and research to help conservation practitioners overcome

constraints to sourcing, producing and using native plant materials in the UK.

For further information, contact Ted Chapman at [email protected], 01444 894192.

mailto:[email protected]

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Contents

Adonis annua L. 4

Bromus interruptus (Hack.) Druce 11

Filago pyramidata L. 15

Galeopsis angustifolia Ehrh. ex Hoffm. 20

Ranunculus arvensis L. 28

Silene gallica L. 35

Torilis arvensis (Huds.) Link 41

Valerianella rimosa Bastard 46

Veronica triphyllos L. 50

Veronica verna L. 55


Propagation Protocol: Adonis annua L.

1 Ecological overview

1.1 Description

Adonis annua L. is an erect annual herb growing to 50cm

(Wilson & King, 2003). Plants bear multiple, branched

stems with finely dissected leaves. Flowers are 15-25mm

in diameter with deep red petals and a dark basal spot

(Wilson & King, 2003). Approximately 30 achenes (dry

fruit) are produced per infructescence, each bearing one

seed, which remains inside a hard covering structure

(Figure 1). Achenes darken in colour and drop readily

when mature. Usually no more than 30 infructescences

are produced per plant (Plantlife, 2009). When grown as a

cultivated population at the MSB in 2014, an average of

259 seed were produced per plant.

1.2 Phenology

Seeds germinate mainly in autumn, but also in spring

(Wilson & King, 2003). Plants flower in June and July,

dispersing seed shortly afterwards. The MSB’s wild UK

collection of A. annua was made in late July, with a spring-

sown cultivated collection made during August.

1.3 Mating system

Adonis annua may be cross-pollinated by insects or self-

pollinated within the bisexual flowers. Pollinator interactions are not described in detail, although the plant

is known to be attractive to bees (Clapham, 1987). Plants grown without pollinators are also able to set a

high proportion of viable seed, suggesting self-pollination is an important mechanism in A. annua

reproduction (Thomann et al., 2015). Seed are heavy and generally remain on the soil surrounding the

mother plant, restricting colonisation of new areas.

1.3 Distribution

Adonis annua is has never been abundant in the UK. The species’ distribution has historically been linked

to areas of chalk and limestone in southern England (Wilson & King, 2003). The UK is the northern limit of

the species’ distribution, with records across the Mediterranean region.

1.4 Habitat

Adonis annua grows on either on arable or other disturbed ground, often on loamy calcareous soils either

on chalk or oolithic limestone (Wilson & King, 2003).

Figure 1. Adonis annua infructescence showing

individual achenes each containing a single

seed. ©RBG Kew


1.5 Co-occurrence with other CitM species

Adonis annua is known to co-occur with Torillis arvensis and Galeopsis angustifolia (Wilson & King, 2003).

1.6 Threats

Adonis annua cannot tolerate herbicides and is easily out-competed by fertilised crops and improved

varieties (Wilson & King, 2003). Plants produce relatively few seeds, resulting in low seed numbers within

soil seed banks (Wilson & King, 2003). Arable species with low seed production show increased probability

of extinction compared to those with high seed production (Saatkamp et al., 2018), with winter annuals

such as A. annua particularly vulnerable to herbicide sprays applied early in their life-cycle (Albrecht, 2003).

2 Seed ecology

2.1 Seed longevity

There is some uncertainty regarding the longevity of A. annua seed in the soil seed bank. Plantlife (2009)

describe the seed as ‘relatively short-lived’, whilst Wilson and King (2003) use the term ‘quite long-lived’.

More recent research by Saatkamp et al. (2009) found that a sample of 40 seeds retained 96.5% viability

after burial in the soil for two and a half years, the highest of all 38 arable species studied. Ongoing research

at the MSB supports the view that A. annua has intermediate or long-term longevity.

2.2 Seed dormancy

Seed dormancy describes a range of mechanisms that prevent seeds germinating, even under favourable

germination conditions. Dormancy may delay germination until the conditions are likely to support healthy

plant growth and stagger germination over multiple growing seasons, helping the population recover from

damaging short-term effects such as drought, disturbance or unfavourable management practices.

Adonis annua appears to display two forms of

dormancy - morphological and physiological

dormancy - commonly described together as

morphophysiological dormancy (Baskin and Baskin,

2014).

As with many species in the Ranunculaceae family,

seeds of A. annua have underdeveloped rudimentary

embryos at dispersal, resulting in morphological

dormancy (Baskin & Baskin, 2014; Figure 2). Embryos

must fully develop inside the seed before germination

can occur. The environmental conditions required to

promote this development differ between species. As

a cornfield annual species, A. annua seeds are

dispersed onto exposed soils, remaining uncovered

for the late summer months. These warm, dry

conditions are likely to promote full embryo

development. Figure 2 Adonis annua seeds with and without the covering

structure. Cut seed displays the underdeveloped,

rudimentary embryo. ©RBG Kew


When the embryo has fully developed, physiological dormancy prevents immediate germination of the

seed. A. annua seeds have a hard, thick covering structure which the radicle (root tip) is unable to penetrate.

This mechanical restriction is overcome naturally by splitting or decay of the covering structures through

repeated cycles of warm-dry and cool-wet conditions across the seasons.

2.3 Dormancy alleviation

Extensive research has been conducted at the MSB into the dormancy alleviation requirements for A.

annua. The most successful protocol identified to date involves a period of dry after-ripening (DAR) in warm,

dry conditions (60% relative humidity, 25°C) to overcome morphological dormancy, followed by a partial

de-husk (removing a small piece of covering structure to expose the radical tip, but without piercing the

seed coat). An alternating temperature of 20/10°C promotes germination following these dormancy-

breaking techniques. In the most successful test, 94% of seed germinated within 105 days, with a mean

time to germination of 36 days.

Step Method Dormancy

1 4 weeks DAR (60%RH, 25°C) Morphological

2 Partial de-husk Physiological

3 Germination temperature (20/10°C, 12/12 photoperiod)

-

To achieve germination without the requirement for partial de-husking, an additional warm/dry and

cool/wet cycle may be included. The most successful germination protocol without partial de-husking is

described in Table 2 – an additional cycle of warm stratification at an alternating temperature of 30/10°C is

followed by cooler alternating germination temperatures of 20/10°C (at which point some germination may

occur), followed by a short period of re-drying at 60% RH and 40°C, before returning to the germination

conditions once more.

Step Method Dormancy

1 4 weeks DAR (60%RH, 25°C) Morphological

2 1 week warm stratification (30/10°C) Physiological

3 4 weeks germination temperature (20/10°C, 12/12 photoperiod)

-

4 4 hours re-drying (60%RH, 40°C) Physiological

5 Germination temperature (20/10°C, 12/12 photoperiod)

-

Table 1. MSB lab protocol for germination of A. annua seeds, listing the corresponding dormancy mechanism

being overcome in each step.

Table 2. MSB lab protocol for germination of A. annua seeds avoiding the need for partial dehusking, listing

the corresponding dormancy mechanism being overcome in each step.


Several other dormancy-alleviation treatments have been applied to A. annua without success, summarised

in Table 3.

Method Result Dormancy

DAR for longer than 4

weeks

Decreases germination Morphological

Surgical methods carried

out prior to DAR (and,

thus, embryo growth)

May lead to the embryo

becoming detached and dying or

producing a tiny seedling.

Physiological

‘Dry-heat shock’ at 103°C No germination Physiological

Smoke solution Germination not increased Physiological

3 Cultivation

In 2014, a modified version of the MSB germination protocol outlined in Table 1 was applied to a wild seed

collection, with plants grown on in the UKNSH production site to provide a large regenerated seed collection

(Table 4).

Propagation work began in January 2014, with treatments reduced to two-week intervals to ensure

seedlings were available for planting in spring. Ideally, seeds would begin the dormancy-breaking

treatments in late summer, to allow the full after-ripening and dormancy-alleviating processes to be

completed and enable germination in autumn. Germination percentage was 48% - it is likely allowing the

full time for DAR and warm stratification would have achieved a higher germination rate.

Figure 3 Photographs of A. annua seedlings, showing the characteristic divided leaves. ©RBG Kew

Table 3. Unsuccessful dormancy alleviation treatments for A. annua.


Seedlings were grown in glasshouse conditions before being planted out into production beds at the end

of May 2014 (Figure 3). Seeds were collected from this regenerated population between 12th August and

2nd September 2014. Following collection, seed material was temporarily stored in paper bags at 20°C and

60% RH to allow continued maturation for one week to ten days, before drying to 15% RH at 15°C for long-

term storage. 282 plants were harvested, yielding 73,056 healthy seed with a viability of 94% - plants grown

under less favourable field conditions are likely to be less productive.

Seed origin: Arable field margin, Oxfordshire.

Date seed collection: 29/07/11

Length of storage: 2 years, 5 months

Pre-treatments: Dry after-ripening at 25°C, 60% RH (2 weeks) Partial de-husk Warm stratification at 30°C (2 weeks)

Germination conditions: 20/10°C, 12/12 photoperiod

Time until germination: Nine weeks (from initiation of pre-treatments)

Germination duration: Three weeks, with sporadic germination thereafter.

Germination percentage: 48%

Germination media: Sand

Growing conditions: Glasshouse with minimum temperature of 16°C for two weeks, then glasshouse with minimum temperature of 2°C.

Growing media: 3:1 mix of Petersfield Peat Free Supreme compost and standard perlite, with 2g/L of Osmocote controlled release fertilizer. Seedlings pricked into 5cm pots then repotted into 9cm pots.

Planting: Planted in open production beds on 28/05/14. Moisture retentive, slightly acidic clay loam with moderate drainage and no addition of fertiliser or organic matter.

Aftercare: Irrigation until established, weeding.

Seed collection:

First collection after 31 weeks (12/08/14 - 02/09/14). Seeds fell readily into the hand when mature. Seed after-ripened at 20°C and 60% RH for one week to ten days before final drying, cleaning and storage in the MSB.

Seed yield and viability: 282 plants yielded 73,056 healthy (filled, uninfested) seed. Viability >94%.

4 Implications for restoration

4.1 Establishing new populations

Adonis annua is suspected to have medium-long term persistence in the soil seed bank and may return with

the reinstatement of management practices that provide adequate germination and establishment niches.

If the species has not been recorded recently or has failed to return under a favourable management

regime, reintroduction is likely to be required.

Table 4. Cultivation data for an A. annua crop at Wakehurst


Sowing onto bare, cultivated ground in late summer mimics the timing of natural seed dispersal and enables

seeds to experience the warm, dry conditions required for after-ripening and dormancy break. Seeds sown

in late summer are more likely to germinate before winter than autumn-sown seed. Seeds which do not

germinate before winter may have successfully overcome morphological dormancy but require further

warm/dry and cool/wet cycling events to overcome physiological dormancy before germinating in spring.

Experience at Wakehurst suggests autumn germinands form larger and more productive plants, although

spring germinands can establish and perform well.

It may be possible to apply dormancy-breaking pre-treatments to stored seed to enhance germination and

establishment in the field. Alternating seeds between warm/dry and cool/wet cycles under controlled

conditions may allow slightly later sowing and increase the percentage of seed germinating in autumn,

although this has not been demonstrated experimentally. Propagating seedlings in cultivation and

introducing them as plug plants would be an alternative means of securing a first generation of flowering

plants and direct dispersal of seed into the soil seed bank.

4.2 Sowing rate

Lang et al. (2016) suggest an optimal sowing rate for arable plant reintroductions of 50-100 seed/m2.

Complex dormancy mechanisms mean only a small proportion of A. annua seed present in the soil are likely

to germinate each year. To establish a large, healthy population it would be advisable to assume a low

germination rate of <5% and increase the sowing rate accordingly – for example, sowing at least 1000 seed

to achieve a population of 50 individuals.

1g of A. annua seed contains approximately 117 individual seeds.

4.3 Site management

Adonis annua is likely to benefit from management regimes that:

• ensure plants are able to disperse seed into the soil seed bank before the crop is cut;

• provide the exposed, open conditions required for seed after-ripening and dormancy-break;

• minimise disturbance of autumn germinating seedlings;

• limit competition from crop or weed species.

Cutting immediately after seed dispersal in July followed by a short fallow period and cultivation in August

or early September will enable after-ripening on the soil surface and promote autumn germination, a

regime consistent with the reported association between A. annua and autumn-sown winter cereals

(Plantlife, 2009). As A. annua is suspected to form a persistent soil seed bank and can also germinate in

spring, populations may also withstand spring cultivation if required to promote other arable species.

If growing A. annua within a crop, reduced fertiliser application and lower cereal density can increase light

levels for arable species. Reduced cereal sowing has been shown to increase rare arable species richness in

cereal crops (Wagner et al., 2017).

In non-arable habitats, disturbance should be carried out to in late summer or early autumn to expose seed

and maintain open ground and high light levels.


5 References

Albrecht, H., 2003. Suitability of arable weeds as indicator organisms to evaluate species conservation

effects of management in agricultural ecosystems. Agriculture, Ecosystems & Environment, 98 (1-3), pp.

201-211.

Baskin, J.M., Baskin, C.C., 2014. Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination,

2nd edition. Academic Press.

Cheffings, C.M. & Farrell, L. (Eds), Dines, T.D., Jones, R.A., Leach, S.J., McKean, D.R., Pearman, D.A., Preston,

C.D., Rumsey, F.J., Taylor, I. 2005. The Vascular Plant Red Data List for Great Britain. Species Status 7, 1-116.

Joint Nature Conservation Committee, Peterborough.

Clapham, A., Tutin, T., Moore, D., 1987. Flora of the British Isles. Third Edition. Cambridge, CUP.

Lang, M., Prestele, J., Fischer, C., Kollmann, J., Albrecht, H., 2016. Reintroduction of rare arable plants by

seed transfer. What are the optimal sowing rates? Ecology and Evolution, 6, 15, pp. 5506–5516.

Plantlife, 2009. Adonis annua species briefing sheet. Available at: www.plantlife.org.uk/uk/discover-wild-

plants-nature/plant-fungi-species/pheasants-eye.

Saatkamp, A., Affre, L., Dutoit, T., Poschlod, P., 2009. The seed bank longevity index revisited: limited

reliability evident from a burial experiment and database analyses. Annals of Botany, 104, 4, pp.715–724.

Saatkamp, A., Affre, L., Dutoit, T., Poschlod, P., 2018. Plant traits and population characteristics predict

extinctions in a long-term survey of Mediterranean annual plants. Biodiversity and Conservation, 27, 10,

pp. 1-14.

Thomann, M., Imbert, E., Cheptou, P., 2015. Is rapid evolution of reproductive traits in Adonis annua

consistent with pollinator decline? Acta Oecologica, 69, pp. 161-166.

Wagner, M., Bullock, J.M., Hulmes, L., Hulmes, S., Pywell, R.F., 2017. Cereal density and N-fertiliser effects

on the flora and biodiversity value of arable headlands. Biodiversity and conservation, 26, 1, pp. 85-102.

Wilson, P., King, M., 2003. Arable plants: a field guide. Wild Guides.

Propagation Protocol: Bromus interruptus (Hack.) Druce of 58

Propagation Protocol: Bromus interruptus (Hack.) Druce


1.1 Description

Bromus interruptus is a robust annual grass, 20-

100cm tall, gaining its name from the gaps that can

sometimes be observed between the spikelets

(Figure 1; Clayton et al., 2006;). The spikelets usually

form in clusters of three and individually measure

approximately 10-17mm in length, with the lemma

bearing an awn up to 8mm long (Wilson & King,

2003). The entire panicle can reach 8cm (Rich &

Lockton, 2002).

1.2 Phenology

Germination occurs in autumn and spring, with

autumn-germinating seeds forming earlier-

flowering and more productive plants (Rich &

Lockton, 2002). Plants flower from May to July,

sometimes extending into early autumn in warm,

damp seasons, with seed dispersal in late summer.

Seed collections from cultivated plants held in the

MSB were made in August. Plants produce abundant

seed which is often retained in the spikelets, causing

seedlings to appear in small clumps.

1.3 Mating system

The mating system of B. interruptus is not described in detail. Rich and Lockton (2002) and Hubbard (1984)

note that the anthers may protrude or be entirely enclosed within the floret, suggesting both outcrossing

and self-pollination can occur. Cleistogamy (self-pollination within unopened flowers) is a common strategy

in other annual bromes (for example, Meyer et al., 2013).

1.4 Distribution

Bromus interruptus is endemic to the UK and was first discovered in 1849 at Odsey in Cambridgeshire. Now

extinct in the wild, the species’ former range extended across south England and East Anglia (Wilson & King,

2003). The species was last recorded in the wild at Pampisford in Cambridgeshire in 1972. Introduced

populations have been recorded in the Netherlands.

1.5 Habitat

Bromus interruptus is associated with agricultural crops and disturbed field edges, typically on calcareous

soils but also occurring in neutral, sand and clay sites (Wilson & King, 2003; Rich and Lockton, 2004).

Figure 1 Bromus interruptus spike, growing in association

with Onobrychis vicifolia. ©Plantsurfer at English

Wikipedia


Historically it was particularly associated with Sainfoin and Clover crops, but also occurred in hay meadows,

fallow land, roadsides and waste ground (Rich & Lockton, 2002).

1.6 Threats

As with many other arable species, improved seed cleaning, improved and competitive crop varieties and

increasing use of artificial fertilisers and herbicides contributed to the decline of B. interruptus (Wilson &

King, 2003). Plants are maintained in cultivation, with an introduced population at Plantlife’s Ranscombe

Farm reserve in Kent.

2 Seed ecology

2.1 Seed longevity

Rich and Lockton (2002) report there is ‘some indication that seeds may be short-lived’ and attempts to

restore lost populations from the soil seed bank appear to have failed. Seed stored under ambient

conditions is reported to have died in four years (Donald, 1980), although the seed can survive for long

periods under optimal storage conditions. One collection has retained 100% viability after 50 years of

storage at 15% equilibrium relative humidity (eRH) and -20°C in the MSB, for example, with two 40-year old

collections retaining >93% viability.

Given the high conservation value of B. interruptus and the importance of the soil seed bank in the recovery

and persistence of annual plant populations, it would be useful to conduct some longevity or seed aging

experiments on this species.

2.2 Seed germination

The MSB holds ten collections of B. interruptus seeds, all of which have germinated successfully (>85%

germination) at a range of temperatures from 10°C to an alternating temperature of 25/10. Tests were

conducted in the presence of light, with total germination reached within one or two weeks.

3 Propagation

RBG Kew has not attempted to grow B. interruptus plants to maturity, although several other institutions

have successfully established and maintained cultivated populations including Cambridge Botanic Garden,

Ness Botanic Garden and a restored population at the Plantlife reserve at Ranscombe Farm.



With no recent recordings of B. interruptus in the wild, establishing new populations will require the

introduction of seed or plant propagules from cultivated or restored populations.

Early autumn is the optimal time for sowing – autumn-sown B. interruptus plants are more vigorous and

produce more seed – although seed may also be sown and germinated in spring. Seed should be sown onto

moist, bare ground when the temperature is likely to remain at or above 10°C until germination is complete.


4.2 Sowing rate


Bromus interruptus does not display seed dormancy and a high proportion of viable seed exposed to

suitable germination conditions may germinate. Initial sowing rates at the lower end of the range suggested

by Lang et al. (2016) may therefore produce good results and make optimal use of scarce seed, although a

higher rate is likely to result in a larger population and promote more rapid development of a large soil seed

bank.

1g of B. interruptus seed contains approximately 382 individual seeds.

Seed production is high (Rich and Lockton, 2002) and populations may become self-sustaining relatively

quickly where appropriate management is in place.

4.3 Long-term management

Bromus interruptus is likely to benefit from management regimes that:


• avoid disturbing autumn-germinating seedlings and young plants;


Cultivation shortly after seed dispersal in late summer or autumn is likely to provide optimal conditions for

B. interruptus, allowing germination and establishment before winter. To avoid disturbing autumn

germinands, there should be no further disturbance until the following year. Bromus interruptus may also

germinate in spring, suggesting periodic spring cultivation may be tolerated where necessary to control

persistent weeds and benefit other arable species. To ensure populations are not lost, it would be prudent

to cultivate no more than half of the site to ensure continuity of seed production.

If growing B. interruptus within a crop, reduced fertiliser application and lower cereal density can increase

light levels for arable species. Reduced cereal sowing has been shown to increase rare arable species

richness in cereal crops (Wagner et al., 2017).

In non-arable habitats, disturbance should be carried out in autumn to maintain open ground and high light

levels.


5 References


C.D., Rumsey, F.J., Taylor, I., 2005. The Vascular Plant Red Data List for Great Britain. Species Status 7: 1-

116. Joint Nature Conservation Committee, Peterborough.

Clayton, W.D., Vorontsova, M.S., Harman, K.T. and Williamson, H., 2006 onwards. GrassBase - The Online

World Grass Flora. http://www.kew.org/data/grasses-db.html. [accessed 16 October 2018]

Donald, D., 1980. Bromus interruptus (Hack.) Druce. Dodo or phoenix? Nature in Cambridgeshire, 23, pp.

49– 51.



Meyer, S., Ghimire, S., Decker, S., Merrill, K., Coleman, C., 2013. The ghost of outcrossing past in downy

brome, an inbreeding annual grass. Journal of Heredity, 104, 4, pp. 476–490.

Rich & Lockton, 2002. Bromus interruptus (Hack.) Druce (Poaceae) - an extinct English endemic. Watsonia.

24, pp. 69–80.

Wagner, M., Bullock, J.M., Hulmes, L., Hulmes, S. and Pywell, R.F., 2017. Cereal density and N-fertiliser

effects on the flora and biodiversity value of arable headlands. Biodiversity and conservation, 26, 1, pp. 85-

102.

Wilson, P. and King, M., 2003. Arable plants: a field guide. Wild Guides.

http://www.kew.org/data/grasses-db.html

Propagation Protocol: Filago pyramidata L. of 58

Propagation Protocol: Filago pyramidata L.


1.1 Description

Filago pyramidata is an annual herb growing to 30cm, with flowering stems branching from a basal rosette

to grow upright or prostrate (Plantlife, 2006). The entire plant is covered in grey hairs (Wilson & King, 2003).

Tiny flowers occur in clusters of around eight to fifteen dense heads, with yellow-tipped pointed bracts.

Each flower produces a single achene (dry fruit) approximately 0.6mm long and bearing pappus hairs

(Plantlife, 2006).

1.2 Phenology

Seeds may germinate at any time of year if exposed to sufficiently warm, moist conditions but peak

germination occurs between October and December then again in March (Plantlife, 2006; Wilson & King,

2003; Rich, 1999). Flowering typically occurs from July to September, although some plants may flower

later. Seed production follows shortly afterwards - the MSB’s UK collections of F. pyramidata seed were

made between August and October (Table 1). Autumn-germinating plants are larger and more productive,

although the over-wintering rosettes may be lost in harsh winters (Rich, 1999).

1.3 Mating system

The mating system of F. pyramidata is not described in detail, although Rich (1999) reports that no

pollinators have been observed visiting flowers and that the plants are probably self-fertile. The flowers are

composed of bisexual and female florets, but lack petals or other structures to promote cross-pollination

(Plantlife, 2006). Seed are dispersed by the wind, aided by the small pappus, and may travel several metres

from the parent plant (Rich, 1999).

1.4 Distribution

Filago pyramidata was once recorded widely across south eastern Britain but is now restricted to a few

sites (Wilson & King, 2003; Rich, 1999). The UK represents the northern edge of the species’ global

distribution, which is centred around west Asia, north Africa and southern and western Europe (Rich, 1999;

Clapham et al., 1987).

1.5 Habitat

Filago pyramidata is associated with warm, dry sites with open vegetation and disturbed soil such as arable

field margins, abandoned quarries, roadsides, paths and hedge banks. The species typically grows in

calcareous, sometimes sandy soils, (Moyse, 2013; Wilson & King, 2003), although plants have been also

recorded on neutral or acidic soil (Rich, 1999).

Ted Chapman & Sarah Pocock

October 2018



Associations with other CitM species are not described, although Filago pyramidata is associated with a

number of other annual and perennial species associated with open, disturbed habitats including Arenaria

serpyllifolia, Anagallis arvensis, Hypericum perforatum and Medicago lupulina (Rich, 1999).

1.6 Threats

The intensification of agriculture on arable land, including the increased use of chemical fertilisers and

herbicides, has been a major driver of the species’ decline (Wilson & King, 2003; Rich 1999). On non-arable

land, urbanisation and infrastructure development, management changes and natural succession to coarse

grassland, scrub and woodland have also reduced the area of suitably open, disturbed habitat. (Plantlife,

2006). The marginal nature of many sites means individuals of F. pyramidata are particularly vulnerable to

chance events (Plantlife, 2006).

2 Seed ecology

2.1 Seed longevity

The longevity of F. pyramidata seed has not been established experimentally, although the literature

suggests that the seed is long-lived and persistent in the soil seed bank. Large numbers of F. pyramidata

individuals have been recorded at sites with no previous records (Moyse, 2013) or after an absence of 10-

15 years (Rich, 1999), suggesting the species is able to initiate new populations from buried seed.

Given the high conservation value of F. pyramidata and the importance of the soil seed bank in the recovery




The MSB holds germination data for 15 UK collections of F. pyramidata (Table 1). In general, seed germinate

readily at temperatures between 10°C and 20°C, typical of autumn or spring in warmer parts of the UK, with

total germination usually reached within three weeks. There is some variation in germination response

between collections – such variation is not uncommon in native species and may be influenced by factors

including environmental conditions at the collecting site, the time of collection, post-harvesting handling

and storage (Baskin & Baskin, 2014).

Some of the MSB’s UK collections (including one from a chalk pit) respond positively to a high alternating

temperature regime, possibly mimicking the hot, exposed habitat of origin.


Seed origin Collection date Germination

>85% Germination

<85%

Cambridgeshire, England 02/10/73 10°C



Essex, England 22/08/07 10°C, 15°C

Kent, England 25/09/91 35/20°C

Kent, England 16/09/08 5°C, 15°C, 35/20°C

Oxfordshire, England 07/08/95 15°C

Oxfordshire, England 05/09/97 15°C

Surrey, England 24/08/09 35/20°C 15°C

Surrey, England 24/08/09 15°C 20°C

Surrey, England 24/08/09 20°C (with Gibberellic acid)

15°C, 20°C

West Sussex, England 30/08/91 25°C, 25/15°C

West Sussex, England (chalk pit)

25/09/91 20°C, 35/20°C 5°C, 10°C, 15°C, 25°C, 25/10°C

West Sussex, England 25/09/91 15°C

West Sussex, England 25/09/91 35/20°C

3. Propagation

RBG Kew has not attempted to grow F. pyramidata plants to maturity. The seed and seedlings are very

small and difficult to handle and may be vulnerable to damping off and other fungal disease (Rich, 1999).



Filago pyramidata appears to form a persistent soil seed bank and has been restored following scrub

clearance and soil disturbance at some former sites (Rich, 1999) although such attempts have not always

succeeded (Plantlife, 2006). If the species has not been recorded recently or has failed to return under a

favourable management regime, reintroduction is likely to be required.

Table 1 Germination data from the MSB’s UK F. pyramidata collections. Tests were carried out with

exposure to light with 8/16 and 12/12 photoperiods.


Sowing seed in autumn mimics natural seed dispersal and takes advantage of the peak germination season

between October and December (Rich, 1999). Seed may also be sown in spring, and it may be prudent to

follow an autumn sowing with a second spring sowing if the over-wintering rosettes have been lost. Seed

should be sown onto bare, recently cultivated ground.

4.2 Sowing rate


Filago pyramidata does not display complex seed dormancy and a high proportion of viable seed exposed

to suitable germination conditions may germinate. Seedling establishment may be low, however, as the

very small seeds and seedlings are likely to be vulnerable to disturbance, disease and herbivory, consistent

with generally higher seedling mortality rates in small-seeded species (Moles and Westoby, 2014). This

would justify sowing at the higher rate recommended by Lang et al. (2016) - preferably higher where

sufficient seed is available.

1g of F. pyramidata seed contains approximately 20,000 individual seeds.


Filago pyramidata is likely to benefit from management regimes that:


• bring buried seed to the soil surface;

• avoid disturbing seedlings and young plants;


Optimal management for F. pyramidata would allow the plants to disperse seed before annual cultivation

in September, allowing seed to germinate and form over-wintering rosettes from October onwards (Rich,

1999). Later cultivation may result in a more limited spring germination – Plantlife (2006) recommend that

all disturbances are complete by January, with no further disturbance until the following autumn. Annual

cultivation may not be required in less competitive sites, with disturbance carried out as necessary to

expose seed at the soil surface and maintain open ground and high light levels.

If growing F. pyramidata within a crop, reduced fertiliser application and lower cereal density can increase




5 References


C.D., Rumsey, F.J., Taylor, I. 2005. The Vascular Plant Red Data List for Great Britain. Species Status 7: 1-116.


Clapham, A.R., Tutin, T.G., Moore, D.M., 1987. Flora of the British Isles. 3rd edition. Cambridge University

Press, Cambridge.



Moles, A., Westoby, M., 2004. Seedling survival and seed size: a synthesis of the literature. Journal of

Ecology, 92, pp. 372-383.

Moyse, R.I., 2013. Response of broad-leaved cudweed Filago pyramidata to cultivation under

Environmental Stewardship at Ranscombe Farm Reserve, Kent, UK. Conservation Evidence, 10, pp.72-76.

Plantlife, 2006. Filago pyramidata species dossier. Available: https://www.plantlife.org.uk/uk/discover-

wild-plants-nature/plant-fungi-species/broad-leaved-cudweed.

Rich, T., 1999. Conservation of Britain's biodiversity IV: Filago pyramidata (Asteraceae), broad-leaved

cudweed. Edinburgh Journal of Botany, 56, 01, pp. 61-73.


effects on the flora and biodiversity value of arable headlands. Biodiversity and conservation, 26, 1, pp.85-

102.


Propagation Protocol

Galeopsis angustifolia

Ehrh. ex Hoffm.

.

Ted Chapman & Sarah Pocock

October 2018

Propagation Protocol: Galeopsis angustifolia Ehrh. Ex Hoffm of 58

Propagation Protocol: Galeopsis angustifolia Ehrh. ex Hoffm.


1.1 Description

Galeopsis angustifolia Ehrh. ex Hoffm. is an erect

annual herb growing to 50cm. Flowers are bilaterally

symmetrical, with a long corolla tube. Each flower

produces four seeds (Figure 1; Wilson & King, 2003).

Growing conditions significantly impact plant size and

the number of flowers produced, with those growing

on the most nutrient poor soils producing only a single

flower (Wilson & King, 2003).

1.2 Phenology

Seeds germinate in late spring (Wilson & King 2003;

Stewart et al., 1994). Plants flower from July to

October (Wilson & King, 2003), with a single plant

capable of producing flowers throughout the summer.

When mature, seeds darken in colour from green to

black and dehisce readily. The MSB’s wild UK

collections of G. angustifolia were made between

August and October, and the MSB’s cultivated

collections were made from July to early October.

1.3 Mating system

Galeopsis angustifolia is an outcrossing species, with pollen transfer by a wide range of insects (Gibson et

al., 2006). Ensuring restoration sites contain a diverse range of more common flowering plants is likely to

support healthy pollinator populations and promote the long-term persistence of G. angustifolia. Pollinator

visitation appears to vary considerably between sites, however, with one population studied relying heavily

on pollination by a single species (Bombus pascuorum, Common Carder Bee). In these cases, interventions

targeted at promoting key pollinator species – augmenting populations of G. angustifolia and other food

plants, for example – may be beneficial. (Gibson et al., 2006).

1.4 Distribution

Galeopsis angustifolia was once widespread and recorded across calcareous soils in England and Wales,

however the species is now restricted to south and south-east England (Wilson & King 2003). The species’

native range extends across western, central and southern Europe (Stewart et al., 1994).

1.5 Habitat

Plants grow in arable fields, coastal vegetated shingle or scree, and other disturbed ground on light,

calcareous soils (JNCC, 2010; Wilson & King, 2003; Stewart et al., 1994).

Figure 1 G. angustifolia inflorescence, showing a cluster of four

immature seeds produced from a single flower. ©RBG Kew



Galeopsis angustifolia is known to co-occur with Torilis arvensis (Wilson & King 2003; Stewart et al., 1994;)

and Adonis annua (Stewart et al., 1994).

1.7 Threats

Galeopsis angustifolia cannot tolerate herbicides and is poorly-competitive within fertilised crops and

improved varieties (Wilson & King 2003; Stewart et al., 1994). As a spring-germinating species, the change

from spring to autumn-sown crops may be a key factor in the species’ decline – plants often fail to set seed

before autumn-sown crops are harvested and the stubble ploughed, preventing the establishment of a

persistent soil seed bank (Stewart et al., 1994).

2 Seed ecology

2.1 Seed longevity

No long-term longevity data are available from Kew databases, although the seed is believed to be long

lived (Wilson & King, 2003).

Galeopsis ladanum, a close relative of G. angustifolia, has been shown to have intermediate seed longevity,

with a sample of 40 seeds retaining 61.9% viability after burial for two and a half years (Saatkamp et al.,

2009). Although not the same species, seed longevity trends may be similar across the Galeopsis genus.

Given the high conservation value of G. angustifolia and the importance of the soil seed bank in the recovery



2.2 Seed dormancy





Seeds of G. angustifolia appear to display complex and potentially variable physiological dormancy. Seeds

have a hard seed coat, imposing a mechanical constriction on the developing embryo and preventing radical

(root) emergence until the seed coat has been broken down or the embryo gains sufficient growth potential

to force the seed coat open. In some cases, removal of the seed coat alone has enabled germination to take

place – in others this had not been sufficient, suggesting additional physiological dormancy mechanisms,

controlled within the internal seed tissue, may also influence G. angustifolia germination.


Extensive research has been conducted at the MSB into the dormancy alleviation requirements of G.

angustifolia (Table 2), resulting in a successful germination protocol for laboratory and seed production use

(Table 1). This involves removal of the seed coat and the endosperm tissue surrounding the embryo (Figure

2), before incubation at 15°C on agar or sand (Figure 3). Using sand appears to promote germination and

seedling development over a range of incubation temperatures, possibly due to reduced fungal growth.


Germination is typically rapid, with maximum germination achieved within 1-3 weeks following embryo

excision.

Step Method

1 Full embryo excision, using forceps and scalpel to remove seed coat and endosperm

2 Incubation at 15°C on agar or sand, 12/12 photoperiod.

Previous germination trials have included the

use of the plant growth sustance gibberellic

acid (GA3) in germination media, soaking seed

in GA3 prior to sowing and removal of the seed

coat alone. Some of these trials resulted in

acceptable levels of germination but the results

were inconsistent and variable between

collections, suggesting considerable intra-

specific variation in dormancy and germination

behaviour.

The MSB is currently conducting a long-term

‘move-along’ experiment to better understand

how dormancy in G. angustifolia is broken

under natural conditions. This technique

involves cycling multiple samples of untreated

seed through a series of temperature regimes

designed to replicate seasonal fluctuations at

the seed dispersal site (Baskin & Baskin, 2003).

This study, now in a second year, suggests

germination occurs slowly and sporadically

over many years.

Pre-treatment Temperature Maximum

Germination

GA3 in germination media at 250mg/l

20°C 0%

25/10°C 0%

GA3 seed soaking at 5g/l

20/10°C

0%

GA3 seed soaking at 10g/l 10%

5°C 10%

Figure 2 G. angustifolia seeds, showing (left-right) whole seed,

seed with seed coat removed, seed with seed coat and

endosperm removed. ©RBG Kew

Figure 3 Excised G. angustifolia embryos on sand, prior to

incubation at 15°C. ©RBG Kew

Table 1 MSB laboratory germination protocol for G. angustifolia


Removal of seed coat, agar as germination media

10°C 30%

15°C 87%

20°C 30%

15/5°C 40%

20/10°C 67%

25/15°C 40%

Removal of seed coat, sand as germination media

5°C 80%

10°C 80%

15°C 80%

20°C 20%

15/5°C 30%

20/10°C 70%

25/15°C 20%

Move-along experiment

Temperatures of 5oC, 20/10oC, 20oC and 10oC. Cycle lengths of 4, 8 and 12 weeks.

Ongoing. Low levels (4%) of germination after 1 year.

3 Cultivation

In 2018, the MSB germination protocol outlined in Table 1 was applied to a wild seed collection and plants

were grown on for the production of regenerated seed for the Colour in the Margins project (Table 3).

Germination following embryo excision is rapid, allowing propagation to take place in spring and provide

mature plants for harvesting in the same year.

Seedlings were grown on in a growth chamber to maximise establishment before being transferred to a

glasshouse (Figure 4). Plants were potted into one litre pots in May, approximately two months after

germination, and began to flower approximately fourteen weeks after germination. Seed production began

about two weeks after flowering (Figure 4) and were collected over a long period between 3rd July and 4th

October 2018. Following collection, seed material was temporarily stored in paper bags at 20°C and 60%

RH to facilitate continued maturation for one week to ten days, before drying to 15% RH at 15°C for long-

term storage.

Table 2 Alternative MSB methods tested for overcoming dormancy in G. angustifolia seeds.


Seed origin: Gloucestershire, England. Scree on limestone

grassland.

Collection date: 01/09/14


Pre-treatments: Rehydration, excision of embryo from the seed coat

and endosperm.

Germination conditions: 15°C

Germination media: Sand

Time until germination: One week

Duration of

germination:

Three weeks

Germination

percentage:

60%

Growing media: 2:1 mix of Petersfield Peat Free Supreme compost

and standard perlite, with 2g/L of Osmocote

controlled release fertiliser. Seedlings pricked into

5cm pots then repotted into 9cm pots.

Figure 4 Photographs of G. angustifolia seedlings, showing tiny seedlings after transfer from agar (left) and established

seedlings (right). ©RBG Kew


Growing conditions: Growth chamber set at 17°C, followed by glasshouse

with minimum temperature 16°C then unheated

polytunnel.

Seedling establishment: Seedlings repotted after two months into 1 litre pots

containing Melcourt nursery compost with 4g/L

Osmocote controlled release fertiliser.

Time to flowering: 14 weeks

Time to seed

production:

16 weeks

Seed collection: The first seed collection occurred on 3/7/18 and

continued until the final collection on 4/10/18. Seeds

change colour from green to brown and can be readily

shaken from the calyx when mature. Seed was after-

ripened at 20°C and 60% RH for one week to ten days

before final drying, cleaning and storage in the MSB.

Seed yield: The estimated seed yield in cultivation is

approximately 350 seeds per plant (to be confirmed).

Yield under natural conditions is likely to be

substantially lower.



Galeopsis angustifolia is suspected to have intermediate to long-term persistence in the soil seed bank and

may return with the reinstatement of management practices that provide adequate germination and

establishment niches. If the species has not been recorded recently or has failed to return under a


It is not possible to apply seed coat removal or embryo-excision techniques prior to sowing in the field.

Seeds must therefore be sown without pre-treatment, resulting in a spread of germination across multiple

years.

Sowing seeds on bare ground in autumn mimics natural seed dispersal and enables seeds to experience the

seasonal temperature fluctuations that may be required to weaken the hard seed coat and promote

internal chemical changes and break physiological dormancy.

4.2 Sowing rate



The long-term move along experiment described above and successful reintroduction work at Cleeve

Common, Gloucestershire (Philips, 2017), suggest that only a small proportion of seed (<5%) is likely to

germinate in the first spring following sowing, with sporadic germination over subsequent years. To

establish a large, healthy population it would be advisable to assume a low germination rate of <5% and

increase the sowing rate accordingly – for example, sowing at least 1000 seed to achieve a population of

50 individuals.

1g of G. angustifolia seed contains approximately 588 individual seeds.

4.3 Site management

Germination of G. angustifolia occurs entirely in the spring and is associated with spring-sown cereal crops

(Plantlife, 2007; Wilson & King, 2003). Cultivation should therefore take place in spring, between February

and April. Cutting should be carried out when at least some seed has been dispersed, with the plants

allowed to regrow in the stubble to disperse additional seed in the late summer and autumn (Stewart et

al., 1994). Fields should be left fallow over winter, leaving seed exposed on the soil surface to promote

dormancy break.

If growing G. angustifolia within a crop, reduced fertiliser application and lower cereal density can increase



In non-arable habitats, disturbance should be carried out to in late summer or early autumn to maintain

open ground and high light levels.


5 References




C.D., Rumsey, F.J., Taylor, I. 2005. The Vascular Plant Red Data List for Great Britain. Species Status 7: 1-116.


Gibson, R. H., Nelson, I. L., Hopkins, G. W., Hamlett, B. J., Memmott, J., 2006. Pollinator webs, plant

communities and the conservation of rare plants: arable weeds as a case study. Journal of Applied Ecology,

43, pp. 246-257.

JNCC, 2010. Species pages for 2007 UK BAP Priority Species: Galeopsis angustifolia. Available at:

http://jncc.defra.gov.uk/_speciespages/319.pdf.

Lang, M., Prestele, J., Fischer, C., Kollmann, J., & Albrecht, H., 2016. Reintroduction of rare arable plants by


Philips, E., 2017. Email with Ellie Philips, 11/12/17.

Plantlife, 2007. Galeopsis angustifolia species briefing sheet. Available at:

https://www.plantlife.org.uk/uk/discover-wild-plants-nature/plant-fungi-species/red-hemp-nettle.

Saatkamp, A., Affre, L., Dutoit, T., Poschlod, P., 2009. The seed bank longevity index revisited: limited

reliability evident from a burial experiment and database analyses. Annals of Botany, 104, 4, pp. 715–724.

Stewart, A., Pearman, D.A. and Preston, C.D., 1994. Scarce plants in Britain. JNCC.

Wagner, M., Bullock, J.M., Hulmes, L. et al. 2017. Biodiversity Conservation, 26: 85


Propagation Protocol: Ranunculus arvensis L. of 58

Propagation Protocol: Ranunculus arvensis L.


1.1 Description

Ranunculus arvensis is an erect annual herb

growing to 50cm, with much-branched stems.

Solitary flowers resemble those of other

buttercup species, however they are smaller and

paler in colour. Each flower produces up to eight

achenes (dry fruit) each containing a single seed.

Achenes are up to 8mm in length with

characteristic spiny husks (Figure 1, Wilson &

King, 2003).

1.2 Phenology

Seed germinate in autumn and winter (Wilson &

King, 2003), with a few seedlings also

germinating in spring (Stewart et al., 1994).

Flowers are borne from May until mid-June.

Achenes mature from green to dark brown in

colour and the covering structure develops into

a woody husk. UK wild seed collections held in

the MSB were collected in August, with

harvesting from cultivated populations between

early July and early September.

1.3 Mating system

Ranunuculus arvensis plants may be bisexual or gynomonoecious (bearing bisexual and female flowers on

the same plant). Cross-pollination is by small flies (Clapham, 1987) and potentially other insects – pollinator

interactions for this species are not described, although other Ranunculus species have been found take a

generalist approach and attract a broad range of insects (Steinbach & Gottsberger, 1996). Although plants

may display protandry (male parts of the flowers develop first) and other mechanisms to favour cross-

pollination these are not present in all cases (Clapham, 1987) and some self-fertilisation is likely to take

place.

1.4 Distribution

Ranunculus arvensis was widespread across lowland England and Wales, extending to Scotland, however

healthy populations are now rare, with scattered sites across the south-west midlands and southern

England (Wilson & King, 2003; Stewart et al., 1994;). The species occurs throughout central and southern

Europe, north Africa and west Asia, though is also declining in north-west Europe (Stewart et al., 1994).

Figure 1 Photograph of R. arvensis flower, showing multiple

green achenes, each containing a single seed. ©RBG Kew


1.5 Habitat

Ranunculus arvensis is associated with arable crops and field margins, although it also occurs on disturbed

ground such as roadsides, most frequently on heavy clay and sometimes calcareous soils (Stewart et al.,

1994; Wilson & King, 2003).


Ranunculus arvensis is known to co-occur with Torilis arvensis (Stewart et al., 1994; Wilson & King, 2003)

and Valerianella rimosa (Stewart et al., 1994).

1.7 Threats

Improved seed cleaning techniques, broad-spectrum herbicides and more competitive crops have led to

significant declines in R. arvensis. Winter annuals such as R. arvensis are particularly vulnerable to herbicide

sprays applied early in the plant’s life cycle (Albrecht, 2003).

2 Seed ecology

2.1 Seed longevity

Accelerated aging experiments under controlled conditions (50°C, 60%RH) in the MSB found R. arvensis was

the longest-lived of 16 Ranunculus species tested (Bird, 2006). Although these tests do not replicate the

conditions experienced by seed in the field, they do support the general view that buried R. arvensis seed

may remain viable in the soil many years (Wilson & King, 2003; Stewart et al., 1994).

2.2 Seed dormancy


germination conditions. Dormancy may delay germination until conditions are likely to support healthy



Ranunculus arvensis appears to display two forms of dormancy - morphological and physiological dormancy

- commonly described together as morphophysiological dormancy (Baskin and Baskin, 2014).

As with many species in the Ranunculaceae family, seeds of R. arvensis have underdeveloped rudimentary

embryos at dispersal, resulting in morphological dormancy (Baskin & Baskin, 2014; Figure 2). Embryos must

fully develop inside the seed before germination can occur. The environmental conditions required to

promote this development differ between species, but may include a period of warm, dry after ripening

following seed dispersal.

When the embryo has fully developed, physiological dormancy prevents immediate germination of the

seed. Ranunculus arvensis seeds have a hard, thick covering structure which the radicle (root tip) is unable

to penetrate. This mechanical restriction is overcome naturally by splitting or decay of the covering

structures through repeated cycles of warm-dry and cool-wet conditions across the seasons.



Research at the MSB has identified a germination protocol for R. arvensis suitable for use in laboratories or

nursery environments (Table 1). To achieve high levels of germination quickly, surgical pre-treatment is

necessary. Removing a section of the hard-covering structure allows the seed to imbibe water and begin

the internal metabolic processes which enable the embryo to elongate unrestricted by the husk. This partial

de-husk should ideally be carried out using forceps and a scalpel under a microscope. Crucially, only the

covering structure should be removed, and the seed coat itself should not be pierced. The material to be

removed should not be adjacent to the embryo, as underdeveloped embryos can detach from the seed and

may die or form tiny seedlings.

In addition to the surgical pre-treatment, high germination rates are promoted by the addition of the plant

growth substance gibberellic acid (GA3) to the germination medium. Although the use of GA3 can lead to

deformed or unhealthy seedling growth, these impacts were reduced by removing seedlings from the

germination medium as soon as germination was observed and providing high light levels to prevent

etiolation and support healthy growth.

Step Method Type of dormancy

1 Partial de-husk Physiological

2 Incubation at 10⁰C on agar containing 250mg/l GA3

Morphological & physiological

Soaking seeds in higher concentrations of GA3, and incubating the seed at alternative temperatures, did not

increase total germination of R. arvensis.

Ranunculus arvensis may achieve high germination percentages without the use of pre-treatments over

longer periods of time. Incubation at 5⁰C for periods of up to 6 months has promoted germination in some

collections but proved unsuccessful in others, suggesting considerable intra-specific variation in dormancy

and germination behaviour.

3 Propagation

In 2018, the MSB germination protocol outlined in Table 1 was applied to a wild seed collection and plants

were grown on for the production of regenerated seed for the Colour in the Margins project (Table 2).

Artificially alleviating dormancy enabled a fast germination response and the production of mature plants

from a spring sowing in March. Germination largely occurred within three weeks, with some additional

sporadic germination for fifteen weeks.

Table 1 MSB laboratory germination protocol for R. arvensis.


Seedlings were pricked out and grown on in a heated glasshouse and then unheated polytunnel. Plants

were repotted into one litre pots throughout May (Figure 2) and began to flower approximately 12 weeks

after germination. Seed production began a week later, with collection between 9th July and 3rd September

2018. Following collection, seed material was stored in paper bags at 20°C and 60% RH to facilitate

continued maturation for one week to ten days, before drying to 15% RH at 15°C for long-term storage.

Seed origin: Former arable land, Cambridgeshire.



Pre-treatments: Partial de-husk

Germination conditions: 10°C, 12/12 photoperiod

Germination media: Agar with 250mg/L of GA3

Time until germination: 11 days

Duration of germination: Three weeks, with sporadic germination to 15 weeks


Growing media: 2:1 mix of Petersfield Peat Free Supreme compost and standard perlite, with 2g/L of Osmocote controlled release fertiliser. Seedlings pricked into 5cm pots then repotted into 1L pots.

Growing conditions: Glasshouse with minimum temperature 16°C, glasshouse with minimum temperature 4°C, unheated polytunnel.

Figure 2 Photographs of R. arvensis seedlings, showing seedlings after transfer from agar (left) and later once seedlings were

established and repotted (right). ©RBG Kew



Time to seed production: 13 weeks

Seed collection:

The first seed collection occurred on 9/7/18 and continued until the final collection on 3/9/18. Seeds dry and change colour from green to brown when mature and can be easily pulled or shaken from the plant.

Seed yield: The estimate seed yield in cultivation is 250 seed per plant (to be confirmed). Seed yield under natural conditions is likely to be substantially lower.



Ranunculus arvensis is believed to have intermediate or long-term persistence in the soil seed bank and

may return with the reinstatement of management practices that provide adequate germination and



Artificial dormancy alleviation techniques for R. arvensis are not practicable for large-scale use.

Reintroduction should therefore take advantage of natural opportunities for dormancy release and

germination, with germination likely to be spread over multiple years.

Sowing seeds in autumn mimics natural seed dispersal and enables seeds to experience the seasonal

temperature fluctuations that may be required to weaken the hard covering structure, promote internal

hormonal changes and break physiological dormancy.

4.2 Sowing rate


The dormancy and germination behaviour of R. arvensis appears to be quite variable, making it hard to

predict germination and establishment success. Whilst high levels of germination are possible, to establish

a large, healthy population it may be prudent to sow at the higher rate recommended by Lang et al. (2016),

or higher where the supply of seed permits.

1g of R. arvensis seed contains approximately 89 individual seeds.

Table 2 Propagation protocol for R. arvensis.


4.3 Site Management

Ranunculus arvensis is likely to benefit from management regimes that:

• ensure the maximum number of seed are able to enter the soil seed bank before the crop is cut;

• provide an opportunity for seed after-ripening and dormancy-break on the soil surface;

• minimise disturbance of autumn germinating seedlings.

Cutting immediately after seed dispersal in August followed by a short fallow period and cultivation in

September or early October is likely to enable after-ripening on the soil surface and promote autumn

germination, a regime consistent with the association between R. arvensis and autumn-sown winter cereals

(Wilson & King, 2003; Stewart et al., 1994). As R. arvensis is believed to form a persistent soil seed bank and

can also germinate in spring, populations may also withstand periodic spring cultivation if required for other

arable species (Plantlife, 2009).

If growing R. arvensis within a crop, reduced fertiliser application and lower cereal density can increase light



In non-arable habitats, disturbance should be carried out to in autumn to maintain open ground and high

light levels.


5 References


effects of management in agricultural ecosystems. Agriculture, Ecosystems & Environment, 98, 1-3, pp. 201-

211



Bird, A. E., 2006. Thermal methods and comparative seed longevity in the genus Ranunculus L. PhD Thesis,

School of Biological and Chemical Sciences, Birkbeck College, University of London.


C.D., Rumsey, F.J., Taylor, I., 2005. The Vascular Plant Red Data List for Great Britain. Species Status 7, 1-


Clapham, A., Tutin, T., Moore, D., 1987. Flora of the British Isles. Third Edition. Cambridge, CUP.

Plantlife, 2009. Ranunculus arvensis species briefing sheet. Available:

https://www.plantlife.org.uk/uk/discover-wild-plants-nature/plant-fungi-species/corn-buttercup.

Steinbach, K., Gottsberger, G., 1994. Phenology and pollination biology of five Ranunculus species in

Giessen, Central Germany. Phyton; annales rei botanicae, 34, pp. 203-218.




102.


Propagation Protocol: Silene gallica L. of 58

Propagation Protocol: Silene gallica L.


1.1 Description

Silene gallica is an erect annual growing to 30cm.

Young plants form a basal rosette followed by a

framework of occasionally-branched stems (Wilson &

King, 2003). Upper parts are covered in sticky,

glandular hairs. Multiple flowers form along stem

branches, each up to 15mm across with five

yellowish-white to pink petals. Seed capsules reach

approximately 10mm long and open at the tip to

release the seeds (Figure 1, Wilson & King, 2003).

Each capsule produces an average of 48 seeds, each

weighing approximately 0.4mg (Plantlife, 2007;

Salisbury, 1961). Seeds are dark brown, kidney-

shaped and approximately 0.8mm in diameter

(Wilson & King, 2003).

1.2 Phenology

Seeds germinate in autumn and spring (Wilson & King, 2003; Stewart et al., 1994). Flowers are produced

over a long period from June-October (Plantlife, 2007), with seed dispersal following shortly afterwards.

The MSB’s wild and cultivated UK collections of S. gallica seed were made between July and October.

1.3 Mating system

Silene gallica flowers are predominantly bisexual, although gynomonoecious (bearing bisexual and female

flowers on the same plant) individuals have been reported (Casimiro-Soriguer et al., 2015). Cross-

pollination by a range of Lepidoptera and bees is reported (CABI, 2018) although pollinator interactions for

this species are not described in detail. Some self-fertilisation is also likely to take place (Plantlife, 2008).

Although most seed is dispersed close to the parent plant (Plantlife, 2008), viscid stems and capsules may

aid seed dispersal by animals or human disturbance (Guthrie-Smith, 1953) and the small, light seed may be

carried by wind.

1.3 Distribution

Although never abundant, S. gallica was widespread across lowland southern UK and Wales, with limited

sites extending to Scotland. The species has declined across its range and is now highly restricted to south-

west coastal areas of England and Wales (Wilson & King, 2003; Stewart et al., 1994). Silene gallica is also

found in dunes in the Channel Islands (Stewart et al., 1994). The southerly distribution is likely influenced

by the inability of S. gallica to tolerate temperatures below -10°C (Stewart et al., 1994).

Figure 1 Silene gallica capsule, showing individual seeds

dispersing and sticking to glandular hairs. ©RBG Kew


1.4 Habitat

Silene gallica grows in light, sandy soils in arable fields of spring and winter crops, wastelands, open coastal

grassland and sand dunes (Preston et al., 2002; Stewart et al., 1994).


Silene gallica is known to co-occur with Filago pyramidata and Valerianella rimosa (Plantlife, 2008).

1.6 Threats

Silene gallica does not compete well with fertilised crops and improved varieties (Wilson & King, 2003).

Seeds are easily cleaned from crop harvests, and abandonment of arable land and conversion of field

margins to grassland has led to declines in suitable arable habitat (Plantlife, 2007). Increased tourism and

clifftop erosion also threaten coastal populations (JNCC, 2010; Plantlife, 2007).

2 Seed ecology

2.1 Seed longevity

In accelerated aging studies conducted at the MSB, S. gallica seeds incubated at 60%RH and 45⁰C showed

no significant loss in viability until they had been stored for more than 100 days, suggesting the seed is

comparatively long-lived. The MSB also holds a S. gallica collection that has retained 98% viability for 36

years under storage conditions of 15% eRH (equilibrium relative humidity) and -20°C. Whilst controlled

trials and long-term dry storage do not replicate conditions experienced by seed in the soil, these data

support the general view (for example, Plantlife 2008) that S. gallica seed are long-lived and persistent in

the soil seed bank.

2.2 Germination

The MSB holds germination data for three UK collections

of S. gallica, displaying variable germination

requirements (Table 1). In two collections, germination

has been straightforward with no evidence of dormancy

and high germination rates at alternating temperatures

of 20/10⁰C. Seeds from the Cornwall collection, by

contrast, show low germination unless pre-treated with

a radicle chip - removing a small portion of seed coat

adjacent to the radicle (root) (Figure 2). Germination is

then very rapid, even at the lower temperature of 10⁰C.

Research is underway to understand potential dormancy

mechanisms in this collection and develop a propagation

protocol without the need for a radical chip. Intra-

specific variation in seed dormancy and germination is

not uncommon in native species and may be influenced

by factors including environmental conditions at the

collecting site, the time of collection, post-harvesting

handling and storage (Baskin & Baskin, 2014).

Figure 2 Silene gallica radicle chip using forceps and

a scalpel under a stereoscope. ©RBG Kew


Silene gallica seed require light to germinate. Even low levels of shading – for example by young crop

seedlings - can prevent germination (Battla et al., 2000).

Seed Origin Collection Date Successful Protocol

Pembrokeshire,

Wales

01/08/68 20/10⁰C (100%

germination)

Essex, England 01/07/95 20⁰C (100%

germination)

Cornwall, England 20/10/99 Radicle chip, 10⁰C

(100% germination)

3 Propagation

In 2018, seeds from the MSB collection of S. gallica originating in Cornwall were germinated and grown on

for the production of regenerated seed for the Colour in the Margins project (Table 2).

Propagation began in late March with a radicle chip and sowing on compost in a heated glasshouse.

Germination was rapid, beginning after one week and continuing for three weeks. Seedlings were sown

directly into 5cm pots to minimise root disturbance then transferred to one litre pots in May, approximately

two months after germination (Figure 3). Seedlings of S. gallica are extremely small and susceptible to

disturbance and herbivory - in cultivation, sciarid fly pose a particular threat - which can lead to total

defoliation of the young plants.

Figure 3 Silene gallica seedlings growing in 5cm plug trays (left) and at the flowering stage (right). ©RBG Kew

Table 1 Germination data from MSB’s UK S. gallica collections. Tests were carried out

with exposure to light with 8/16 and 12/12 photoperiods.


Plants began to flower approximately twelve weeks after germination (Figure 3), and seed production

began about three weeks later. Seeds were collected from this regenerated population between 18th July

and continued at the time of writing in mid-October 2018. Entire flowering stems were cut when at least

50% of the seeds were at the point of dispersal. Following collection, seed material was temporarily stored

in paper bags at 20°C and 60% RH to facilitate continued maturation for one week to ten days, before drying

to 15% RH at 15°C for long-term storage.

Seed origin: Arable field, West Pentire, Cornwall



Pre-treatment: Radicle chip (removing a portion of the seed coat adjacent to the radicle)

Germination conditions: Heated glasshouse (min 16°C).

Germination media: 2:1 Petersfield Peat Free Supreme potting compost and standard perlite in 5cm plug trays. Seeds covered with a thin layer of fine vermiculite.

Time until germination: One week

Duration of germination: Three weeks


Growing media: Seedlings repotted 15/5/18, 7 weeks after sowing, into 1 litre pots containing Melcourt nursery compost with 4g/L Osmocote controlled release fertiliser.

Growing conditions: Established seedlings moved to a cool glasshouse (min 4°C).


Time to seed production: 15 weeks

Seed collection:

The first seed collection occurred on 18/7/18 and was continuing at the time of writing in mid-October 2018. Plants simultaneously bear unopened buds, flowers, immature and mature seed. Seeds change colour from green to brown when mature and can be easily shaken from the capsule.

Seed yield: The seed yield in cultivation is likely to be in excess of 1000 seed per plant (to be confirmed). Yield under natural conditions is likely to be lower.

Table 2 Propagation protocol for S. gallica.




Silene gallica is likely to have long-term persistence in the soil seed bank and may return with the

reinstatement of management practices that expose buried seed to the light and reduce competition with

other plants. If the species has not been recorded recently or has failed to return under a favourable

management regime, reintroduction is likely to be required.

Sowing in early autumn mimics natural seed dispersal and provides an opportunity for autumn and spring

germination. As a poor competitor, S. gallica should be reintroduced to bare, recently cultivated ground,

ensuring seed are exposed to high light levels and are neither buried in the soil nor shaded by other plants.

Seeds which do not germinate in the autumn/winter after sowing may germinate in the following spring.

4.2 Sowing rate


In general, S. gallica does not display complex seed dormancy and a high proportion of viable seed exposed

to suitable germination conditions (moist soil, high light availability and moderate temperatures) may

germinate. Seedling establishment is likely to be low, however, as experience at Wakehurst suggests the

small seedlings are vulnerable to disturbance and herbivory, consistent with generally higher seedling

mortality rates in small-seeded species (Moles and Westoby, 2014). This would justify sowing at the higher

rate recommended by Lang et al. (2016) - preferably higher where sufficient seed is available.

1g of S. gallica seed contains approximately 3077 individual seeds.


Silene gallica is likely to benefit from management regimes that:


• expose buried seed to light;



Silene gallica can germinate following cultivation in mid-autumn or early-spring, provided plants are able

to complete their life cycle before the ground is disturbed again (Plantlife, 2008). As a poor competitor,

reduced fertiliser application and lower cereal density is likely to be particularly beneficial for S. gallica,

consistent with the general association between reduced cereal density rare arable species richness

(Wagner et al., 2017).

Silene gallica may also persist in headlands, field margins and other habitats where large vegetation gaps

and ongoing disturbance create opportunities for seeds to geminate and establish. Where natural processes

(rabbit grazing, unstable soils etc.) are insufficient to create these niches, additional annual disturbance

may be necessary (Plantlife, 2008).


5 References


effects of management in agricultural ecosystems. Agriculture, Ecosystems & Environment, 98, 1-3, pp.201-

211.



Batlla, D., Kruk, B.C. and Benech‐Arnold, R.L., 2000. Very early detection of canopy presence by seeds

through perception of subtle modifications in red: far red signals. Functional Ecology, 14, 2, pp. 195-202.

CABI, 2018. Invasive Species Compendium: Silene gallica datasheet. Available:

https://www.cabi.org/isc/datasheet/117143.

Casimiro-Soriguer, I., Buide, M., Narbona, E., 2015. Diversity of sexual systems within different lineages of

the genus Silene. AoB Plants, 7.




Guthrie-Smith H, 1953. Tutira - The Story of a New Zealand Sheep Station, 3rd edition. William Blackwood

and Sons, Edinburgh, pp. 282-285.

JNCC, 2010. Species pages for 2007 UK BAP Priority Species: Silene gallica. Available:

http://jncc.defra.gov.uk/_speciespages/575.pdf




Ecology, 92, pp. 372-383.

Plantlife, 2007. Silene gallica species briefing sheet. Available: https://www.plantlife.org.uk/uk/discover-

wild-plants-nature/plant-fungi-species/small-flowered-catchfly.

Plantlife, 2008. Silene gallica species dossier. Available: www.plantlife.org.uk/uk/discover-wild-plants-

nature/plant-fungi-species/small-flowered-catchfly.

Preston, C.D., Pearman, D.A., Dines, T.D., 2002. New Atlas of the Flora of Britain and Ireland. Oxford

University Press, London.

Salisbury E., 1961. Weeds and Aliens. Collins, London.

Stewart, A., Pearman, D.A., Preston, C.D., 1994. Scarce plants in Britain. JNCC.

Wagner, M., Bullock, J.M., Hulmes, L., Hulmes, S., Pywell, R.F., 2017. Cereal density and N-fertiliser effects

on the flora and biodiversity value of arable headlands. Biodiversity and conservation, 26, 1, pp.85-102.

Wilson, P., King, M., 2003. Arable plants: a field guide. Wild Guides.

http://jncc.defra.gov.uk/_speciespages/575.pdf

Propagation Protocol: Torilis arvensis (Huds.) Link of 58

Propagation Protocol: Torilis arvensis (Huds.) Link


1.1 Description

Torilis arvensis is an annual, rarely biennial,

herb growing to 40cm. Inflorescences form

umbels approximately 10-25mm in diameter.

Individual flowers are small, approximately

2mm across, and bear white or pale pink petals.

Fruit form in late summer and are borne in

pairs, are 4-6mm long and covered with bristly

hairs with incurved tips (Figure 1; Wilson & King,

2003).

1.2 Phenology

Torillis arvensis seed germinate in late autumn

and winter, between October and December

(Wilson & King, 2003), with seedlings forming

an overwintering rosette. Flowers are produced from July to September (Wilson & King, 2003), with seed

production shortly afterwards. The MSB’s UK wild collection of T. arvensis was made in late September.

Overwintering rosettes may not survive very harsh winters (Stewart et al., 1994).

1.3 Mating system

Torillis arvensis is an andromonecious species, bearing bisexual and staminate (male) flowers on the same

plant. The species is also weakly protandrous, with male parts of the flower maturing first. Whilst these are

typically strategies to promote cross-pollination, male and female flowering phases have been observed to

overlap – this, together with the small flower size and lack of obvious pollinator interactions, suggests self-

fertilisation is widespread (Koul, et al., 1993; Gupta, et al., 1985). Incurved hairs on the seed husk promote

dispersal by animals.

1.4 Distribution

The species was formerly widespread across lowland chalk areas of southern and eastern England but has

declined across its range and is currently most frequent in Somerset and East Anglia (Wilson & King, 2003).

T. arvensis is most commonly found on heavy calcareous clay soils (Stewart et al., 1994). The UK is at the

northern edge of the species’ range, which extends to western, southern and central Europe and into south-

western Asia (Stewart et al., 1994).

1.5 Habitat

Torilis arvensis is associated with the field margins of winter-sown cereal crops and disturbed ground such

as wasteland and railway sidings adjacent to arable land (Plantlife, 2006; Stewart et al., 1994).

Figure 1 Photograph of T. arvensis fruits, showing bristly hairs

covering the outer husk. ©RBG Kew



Torilis arvensis is known to co-occur with Ranunculus arvensis, Adonis annua, Valerianella rimosa and

Galeopsis angustifolia (Plantlife, 2006; Wilson & King, 2003; Stewart et al., 1994).

1.7 Threats

Torilis arvensis does not compete well with fertilised crops and improved varieties. Early harvesting and

ploughing may prevent this late-flowering species forming and dispersing seed (Wilson & King, 2003) and,

like other winter annuals, seedlings are vulnerable to herbicides applied early in their life cycle (Albrecht,

2003; Stewart et al., 1994).

Improved arable seed cleaning and the succession of arable field margins to grassland – either as a

deliberate policy or abandonment - may also threaten T. arvensis populations (Plantlife, 2006).

2 Seed ecology

2.1 Seed longevity

There is some disagreement in the literature regarding the longevity of T. arvensis in the soil seed bank,

although the available research suggests seed can persist for at least three to four years and potentially

longer (Plantlife, 2006).

No long-term longevity data are available from Kew databases and, given the importance of the soil seed

bank in the recovery and persistence of annual plant populations, it would be useful to conduct some

longevity or seed aging experiments on this species.


Torilis arvensis seeds do not display any dormancy mechanisms and will germinate readily when the

germination conditions are met. The MSB’s UK wild collection of T. arvensis has been tested under three

conditions (Table 1). Incubation at a constant temperature of 10°C or alternating temperatures of 25/10°C

both resulted in high germination (≥90%). Germination began within two weeks and continued sporadically

for up to three months. Seed exposed to a period of cold stratification period of eight weeks followed by

incubation at an alternating temperature regime of 25/10° was more prone to rotting and did not germinate

readily.

Incubation temperature Germination

8wks 5°C stratification, followed by 25/10°C 0%

10°C 90%

25/10°C 98%

Table 1 Germination data from the MSB’s UK T. arvensis collections. Tests were carried

out with exposure to light in 8/16 or 12/12 photoperiods.


3 Propagation

In 2018, seed from the MSB’s wild UK collection of T. arvensis was propagated to produce a regenerated

seed for the Colour in the Margins project (Table 2).

Seeds were sown in January 2018 on agar plates and incubated at an alternating temperature of 25/10°C.

Germination began after twelve days, with final germination reached after three months.

Seedlings were grown on in 5cm pots in a growth chamber providing supplementary lighting to sustain

growth until natural light levels increased in late March. Seedlings were transferred to a glasshouse and

then an unheated polytunnel, and were potted into one litre pots in April, three months after germination

began (Figure 2). Plants began to flower in July, however the entire population was suddenly lost – rotting

at the roots and stem base suggest a short period of over-watering combined with exceptionally high

summer temperatures may have been the cause. The plants also proved very susceptible to aphid

infestation in cultivation.

Seed origin: Edge of arable field, Acton, Suffolk


Length of storage: Twenty years, four months

Pre-treatment: None

Germination conditions: 25/10°C, 12/12 photoperiod

Germination media: Agar

Time until germination: Twelve days

Duration of germination: Three months

Figure 2 Torilis arvensis seedlings, showing cotyledons and characteristic true leaves (left), and established plants shortly

before flowering (right). ©RBG Kew



Growing media: 2:1 Petersfield Peat Free Supreme potting compost and standard perlite in 5cm plug trays.

Growing conditions: Growth chamber set at 17°C, followed by a glasshouse with minimum temperature 16°C then an unheated polytunnel.

Establishment: Seedlings repotted after three months into 1 litre pots 1 litre pots containing Melcourt nursery compost with 4g/L Osmocote controlled release fertiliser.



Torilis arvensis is believed to have at least medium-term persistence in the soil seed bank and may return

with the reinstatement of management practices that provide suitable germination niches and reduced

competition with other plants. If the species has not been recorded recently or has failed to return under a


Sowing in early-mid autumn mimics natural seed dispersal and permits rapid germination in autumn and

early winter. As a poor competitor, T. arvensis should be reintroduced to bare, recently cultivated ground.

Although the species is generally understood to germinate exclusively in autumn some studies have also

reported limited spring germination (Plantlife, 2006).

4.1 Sowing rate


Torilis arvensis does not display seed dormancy and a high proportion of viable seed exposed to suitable

germination conditions may germinate. Initial sowing rates at the lower end of the range suggested by Lang

et al. (2016) may produce good results, although a higher rate is likely to result in a larger population and

promote more rapid development of a large soil seed bank.

1g of T. arvensis seed contains approximately 500 individual seeds.


Torilis arvensis is likely to benefit from management regimes that:




Torilis arvensis has a relatively long life-cycle, producing seed later than most other cornfield annuals.

Where possible, cutting should be delayed until the seed has been dispersed, with stubble left unploughed

to allow plants to continue flowering and dispersing seed. Cultivation should take place in autumn, with no

Table 2 Propagation protocol for T. arvensis. To be updated with the results of a second attempt in 2019.


further disturbance until the following autumn. Plantlife (2008) suggest periodic spring cultivation may be

tolerated where necessary to control persistent weeds and benefit other arable species - to ensure

populations are not lost, it would be prudent to cultivate no more than half of the site to ensure continuity

of flowering and seed production.

If growing T. arvensis within a crop, reduced fertiliser application and lower cereal density can increase light

levels. Reduced cereal sowing has been shown to increase rare arable species richness in cereal crops

(Wagner et al., 2017).

In non-arable habitats, disturbance should be carried out in autumn to maintain open ground and high light

levels.

5 References



211.

Cheffings, C.M., Farrell, L., (Eds), Dines, T.D., Jones, R.A., Leach, S.J., McKean, D.R., Pearman, D.A., Preston,



Gupta, S.K., Hamal, I.A., Koul, A.K. Proc., 1985. Reproductive biology of Torilis arvensis (Hudson) Link. Indian

Acad. Sci. (Plant Sci.), 95, 227.

Koul, P., Sharma, N., Koul, A., 1993. Pollination biology of Apiaceae. Current Science, 65, 3, pp. 219-222.



Plantlife, 2006. Torilis arvensis species dossier. Available: https://www.plantlife.org.uk/uk/discover-wild-

plants-nature/plant-fungi-species/spreading-hedge-parsley.



effects on the flora and biodiversity value of arable headlands. Biodiversity and conservation, 26, 1, pp.85-

102.


Propagation Protocol: Valerianella rimosa Bastard of 58

Propagation Protocol: Valerianella rimosa Bastard


1.1 Description

Valerianella rimosa is a slender, branched annual

herb growing to 30cm (Plantlife, 2008).

Inflorescences form in terminal clusters, usually with

additional single flowers in the branch axils. Flowers

grow to 2mm in diameter with five white petals which

are occasionally tinged pink. Fruits of V. rimosa are

approximately 1.5mm across and resemble a grape

pip, with a single tooth at the apex (Wilson & King,

2003).

1.2 Phenology

Seed germinate predominantly in autumn but may

also germinate in spring (Plantlife, 2008; Wilson &

King, 2003). Plants form a rosette from which a single, erect stem forms in summer and branches to bear

flowers between June and August. Autumn germinands may flower earlier than spring germinands

(Plantlife, 2008) and may be more productive. Seed is dispersed shortly after flowering – four of the MSB’s

UK collections of V. rimosa seed were made in July and August, with one collection in early September.

1.3 Mating system

The mating system of V. rimosa is not described in detail. Flowers are bisexual (Stace, 2010) and it is likely

both cross and self-pollination occur, as observed in related Valerianella species (for example, Muminovic

et al., 2018). The fruits do not have any obvious adaptations to aid dispersal (Plantlife, 2008).

1.4 Distribution

Although the species was never abundant, V. rimosa was formerly scattered across lowland southern

England and Wales. The species has now declined to a handful of sites, concentrated in southern and south-

west England (Plantlife 2008; Wilson & King, 2003).

1.5 Habitat

Valerianella rimosa is strongly associated with arable fields and field margins and may be found within both

winter and spring-sown crops. Plants have also been recorded at coastal sites and other disturbed ground,

such as quarries and chalk tracks (Plantlife, 2008). Historically associated with calcareous soils, remaining

populations are found on a variety of acidic, sandy, clay and silt soils (Plantlife, 2008; Wilson & King, 2003).


Valerianella rimosa is known to occur with Torilis arvensis, Silene gallica and Ranunuclus arvensis (Plantlife,

2008; Wilson & King, 2003)

Figure 1 Valerianella rimosa fruit, each containing a single

seed. ©RBG Kew


1.6 Threats

Valerianella rimosa is susceptible to herbicides and is easily out-competed by fertilised crops and improved

crop varieties (Wilson & King, 2003). Seeds are easily cleaned from crop harvests and natural succession of

arable field margins to grassland may also threaten V. rimosa populations (Plantlife, 2008). At coastal sites,

populations may be vulnerable to cliff erosion (Plantlife, 2008)

2 Seed ecology

2.1 Seed longevity

The longevity of V. rimosa seed has not been established experimentally, although other Valerianella

species are believed to be long-lived (Plantlife, 2008).

Given the high conservation value of V. rimosa and the importance of the soil seed bank in the recovery




The MSB holds germination testing data for five UK collections of V. rimosa (Table 1). In general, these data

suggest that V. rimosa will germinate without pre-treatment at temperatures of 10°C and alternating

temperatures of 25°C and 10°C, although the germination rate and percentage is variable between

collections. In one collection, germination was promoted by a period of cool incubation at 10°C for four

weeks followed by an alternating temperature regime of 25/10°C. Separate germination peaks were

observed at each temperature – a first within 2 weeks of incubation at 10°C, then a second 2 weeks into

incubation at the alternating temperature regime.

Variation within and between collections of the same native species is not uncommon and may be

influenced by factors including environmental conditions at the collecting site, the time of collection, post-

harvesting handling and storage (Baskin & Baskin, 2014).

The addition of gibberellic acid (GA3), a plant growth substance, to the growing media has promoted higher

and faster levels of germination. More research is required to determine whether dormancy mechanisms

are present in some collections and whether the failure of seed to germinate in winter is due to the

imposition of dormancy (Plantlife, 2008) or temperatures below the germination threshold.

Seed origin Collection date Germination >85% Germination <85%

Somerset, England 14/08/98 25/10°C GA3 10°C GA3

20°C GA3

Oxfordshire, England 13/07/01 10°C then 25/10°C

Oxfordshire, England 13/07/01 25/10°C GA3

10°C 4wks > 25/10°C GA3 5°C 8wks > 25/10°C GA3


Hampshire, England 11/08/06 10°C 25/10°C

Hampshire, England 14/07/16 10°C 10°C 4wks > 25/10°C

3. Propagation

RBG Kew has not attempted to grow V. rimosa plants to maturity.



Valerianella rimosa is believed to be at least moderately long-lived in the soil seed bank (Plantlife, 2008)

and may return with the reinstatement of management practices that provide adequate germination and



Sowing seed in autumn mimics natural seed dispersal and provides an opportunity for autumn germination

and the establishment of larger and more productive plants (Plantlife, 2008). Seed which does not

germinate in autumn may remain dormant or quiescent in the soil and germinate in spring, when further

sowing may also take place. Seed should be sown onto bare, recently cultivated ground.

4.2 Sowing rate


The germination behaviour of V. rimosa appears to be variable, making it hard to predict germination and

establishment success. Whilst high levels of germination are possible, to establish a large, healthy

population it may be prudent to sow at the higher rate recommended by Lang et al. (2016), or higher where

the supply of seed permits.

1g of V. rimosa seed contains approximately 814 individual seeds.


Valerianella rimosa is likely to benefit from management regimes that:


• bring buried seed to the soil surface;



Table 1 MSB germination data for UK collections of V. rimosa.


Optimal management for V. rimosa would allow the plants to disperse seed before annual cultivation in

September, allowing seed to germinate before winter with no further disturbance until the following

autumn. As seed is also able to germinate in spring, populations may withstand periodic spring cultivation

if necessary to control problematic weeds or promote other rare annual species.

If growing V. rimosa within a crop, reduced fertiliser application and lower cereal density can increase light



5 References






Muminovic, J., Melchinger, E., Lübberstedt, T., 2018. Genetic diversity within lamb's lettuce (Valerianella

locusta L.) and across related species determined by AFLP markers. Plant Breeding, 123, pp. 460-466.

Plantlife, 2008. Valerianella rimosa species dossier. Available: http://www.plantlife.org.uk/uk/discover-

wild-plants-nature/plant-fungi-species/broad-fruited-cornsalad.



102.


Propagation Protocol: Veronica triphyllos L. of 58

Propagation Protocol: Veronica triphyllos L.


1.1 Description

Veronica triphyllos is a low-growing annual herb reaching 15cm. Flowers are 3-4mm in diameter, with deep

blue petals that are shorter than the surrounding calyx. Fruit form in capsules, each 6-7mm long, deeply

lobed and bearing two fruit (Wilson & King, 2003).

1.2 Phenology

Germination occurs in early autumn (Plantlife, 2009; Wilson & King, 2003) with seedlings emerging from

the soil in January (Albrecht et al., 2000; Farrell, n.d.). Bare soil is essential, as V. triphyllos will not tolerate

winter competition (Farrell, n.d.). Flowers appear as early as February, with most produced between March

and May. Local environmental conditions influence seed maturation and dispersal, which typically occur

from April to June (Farrell, n.d.). The MSB holds collection data for six UK collections of V. triphyllos, one of

which was made in April and five in May. Plants die and rapidly disappear after seed dispersal.

1.3 Mating system

In a study using pollen/ovule ratios and other reproductive traits to infer mating systems in Veronica species

(Scalone & Albach, 2013), V. triphyllos is described as a self-compatible, facultative autogamous species –

self-pollination is the primary form of reproduction, but outcrossing may also occur. Seed is not adapted

for widespread dispersal, so colonisation of new sites is restricted (Albrecht et al., 2000).

1.4 Distribution

Veronica triphyllos has historically been restricted to a few sites in East Anglia and Yorkshire, but now

remains at two sites in the UK (Wilson & King, 2003). The species is more widespread in continental Europe

in dry grassland and disturbed habitats, with a distribution extending south from Sweden and Latvia.

Although rare in southern Europe, populations have been recorded from North Africa and western Asia

(Farrell, n.d.).

1.5 Habitat

Veronica triphyllos is associated with arable field margins and other disturbed habitats including tracks,

waste land and gravel pits, typically on calcareous or slightly acidic sandy soils (JNCC, 2010; Wilson & King,

2003; Farrell, n.d.).


None known.

1.7 Threats

A poorly-competitive species, V. triphyllos is very sensitive to competition from fertilised crops and

improved varieties (Wilson & King, 2003; Farrell, n.d.). Spring cultivation can disturb plants before they are

able to disperse seed (Albecht et al., 2000) and several former sites have been lost to development (Wilson


& King, 2003; Farrell, n.d.). Winter annuals, such as V. triphyllos, are also particularly vulnerable to herbicide

sprays applied early in their life-cycle (Albrecht, 2003).

2 Seed ecology

2.1 Seed longevity

The longevity of V. triphyllos seed in the soil seed bank has not been established experimentally, although

Albrecht et. al. (2000) found moderate levels of V. triphyllos seed in the soil in years when no seed producing

plants were recorded, concluding that the species is able to form a persistent soil seed bank.




Under optimal ex situ storage conditions V. triphyllos seed appear to be long-lived – two UK collections held

in the MSB have retained >95% viability after 25 years under storage conditions of 15% eRH (equilibrium

relative humidity) and -20°C.

2.2 Seed dormancy





The MSB holds germination data for four UK collections of V. triphyllos (Table 1). Variation in embryo size

was recorded during testing, suggesting some embryos may not be fully developed at the point of dispersal,

resulting in morphological dormancy. The environmental conditions required to promote embryo

development and break morphological dormancy vary from species to species (Baskin & Baskin, 2014).

Although these have not been established experimentally for V. triphyllos, exposing imbibed seed to warm

summer temperatures promoted ripening and dormancy release in the related winter annual V. hederifolia

(Roberts & Neilson, 1981).


Germination in European populations of V. triphyllos has been shown to occur at a range of constant

temperatures between 3°C and 20°C and alternating temperatures of 5/15°C and 10/25°C. Optimal

temperatures are between 7°C and 15°C, with germination strongly suppressed above 20°C (Albrecht et al.,

2000). This is consistent with germination in autumn, although it is not known whether seeds used in this

study were freshly harvested or had been exposed to a period of after-ripening or storage.

In the laboratory, high germination rates were secured by the addition of the plant growth substance

gibberellic acid (GA3) to the germination media and incubation at alternating temperatures of 25/10°C or

20/10°C. Germination typically began within 7 days, with maximum germination within 3 weeks.


Seed origin Collection date Germination >85%

Germination <85%

Norfolk, England 24/05/76 20/10°C GA3 5°C GA3

15°C 20°C 25/10°C GA3 25°C 4wks > 25/10°C 5°C 4wks > 25/10°C GA3 25/10°C 4wks > 15°C

Norfolk, England 24/05/76 25/10°C 25/10°C GA3

15°C 20°C 25°C 2°C 4wks > 25/10°C

Norfolk, England 24/05/76 25/10°C GA3

15°C 20°C 25°C 25/10°C 2°C 4wks > 20°C

Norfolk, England 25/10°C GA3

15°C 20°C 25°C 25/10°C 2°C 4wks > 25/10°C

3 Propagation

RBG Kew has not attempted to grow V. triphyllos plants to maturity.



Veronica triphyllos is believed to be at least moderately long-lived in the soil seed bank and may return with

the reinstatement of management practices that provide adequate germination and establishment niches.

Albrecht et. al. (2000), however, note that the soil seed bank may be quickly exhausted if management

practices allow buried seed to germinate but prevent the plants completing their life cycle. If the species

has not been recorded recently or has failed to return under a favourable management regime,

reintroduction is likely to be required.

Table 1 MSB germination data for UK collections of V. triphyllos.


Sowing in mid to late summer would expose seed to the seasonal temperature cycles that may be required

to promote embryo-development and dormancy release before the cool germination temperatures prevail

in autumn. Seed should be sown on bare, recently cultivated ground with minimal competition from crops

or other plants.

4.2 Sowing rate


The possible presence of dormancy in V. triphyllos, the lack of certainly around how these mechanisms

operate and the sensitivity of the species to competition make it hard to predict germination and

establishment success. Whilst high levels of germination are possible, to establish a large, healthy

population it may be prudent to sow at the higher rate recommended by Lang et al. (2016), or higher where

the supply of seed permits.

Albrecht et. al. (2000) report that where at least four individuals are observed per square metre, seed

production can reach 500/m2 in productive years, although is more often below 100/m2.

1g of V. triphyllos seed contains approximately 2,336 individual seeds.


Veronica triphyllos is likely to benefit from management regimes that:

• ensure plants are able to complete their life cycle and disperse seed before crops are cut or

disturbed;

• expose freshly-dispersed or buried seed to warm summer temperatures at the soil surface;


• severely limit competition from crop or weed species while the plant is in growth.

Veronica triphyllos is strongly associated with winter cereal crops (Albrecht, 2002), benefitting from autumn

cultivation between September and November with no further disturbance until seed dispersal is complete

in May-June the following year (Plantlife, 2009; Wilson & King, 2003;). Allowing a short fallow period for

seed to ripen at the soil surface may be helpful, as may cultivation in early autumn to bring buried seed to

the soil surface while temperatures are still relatively high. Populations may be severely reduced by weed

control in early spring and lost altogether where fields are ploughed in spring (Albrecht, 2002).

If growing V. triphyllos within a crop, reduced fertiliser application and lower cereal density is likely to be

beneficial for this non-competitive species. In general, reduced cereal sowing rates have been shown to

increase rare arable species richness in cereal crops (Wagner et al., 2017).


5 References

Albrecht, H., Mayer, F., Mattheis, A., 2000. Veronica triphyllos L. in the Tertiärhügelland landscape in

southern Bavaria – an example for habitat isolation of a stenoeceous plant species in agroecosystems.

Zeitschrift für Ökologie und Naturschutz, 8, 4, pp.219-226.



211.




JNCC, 2010. Species pages for 2007 UK BAP Priority Species: Veronica triphyllos. Available:


Farrell, L, no date. Veronica triphyllos species account, Online Atlas of the British and Irish Flora. Available:

https://www.brc.ac.uk/plantatlas/plant/veronica-triphyllos.

Plantlife, 2009. Veronica triphyllos species briefing sheet. Available:

https://www.plantlife.org.uk/uk/discover-wild-plants-nature/plant-fungi-species/fingered-speedwell.

Roberts, H., Neilson, J., 1982. Role of Temperature in the Seasonal Dormancy of Seeds of Veronica

hederifolia L. The New Phytologist, 90, 4, pp. 745-749.

Scalone, R. , Kolf, M. and Albach, D. C. (2013), Mating system variation in Veronica (Plantaginaceae):

inferences from pollen/ovule ratios and other reproductive traits. Nordic Journal of Botany, 31, pp. 372-

384.



102.


Propagation Protocol: Veronica verna L. of 58

Propagation Protocol: Veronica verna L.


1.1 Description

Veronica verna is an erect annual herb growing to 15cm with sometimes branched flowering stems. Flowers

are 2-3mm in diameter, with sky-blue petals and short stalks. Fruits form in lobed, yellowish-brown

capsules, with each capsule containing two fruit, (Wilson & King, 2003).

1.2 Phenology

Veronica verna seed predominantly germinate in spring, although autumn germination may occur in wet

years (Wilson and King, 2003; Farrell, n.d.). Flowers are produced between late March and June, with the

inflorescence extending over the season to form a fruiting raceme. Seed is ripened and dispersed

throughout the season. The MSB holds detailed collecting data for six UK collections of V. verna, five of

which were made in June and one in early July.

1.3 Mating system

The reproductive system and pollinator interactions of V. verna are not described. Mating systems within

the Veronica genus are extremely diverse but studies on similar annual Veronica species (Scalone et. al.,

2015) suggests V. verna is likely to be at partially or predominantly self-pollinated.

1.3 Distribution

There are very few records of V. verna in Great Britain, and the species is now restricted to a cluster of small

populations in Suffolk (Farrell, n.d.). Populations in Norfolk and introduced populations in Devon appear to

have been lost. The species is widely scattered across continental Europe, western Asia and Morocco

(Farrell, n.d.).

1.4 Habitat

Veronica verna is associated with short grassland and open, sparsely-vegetated habitats on infertile, sandy,

calcareous soils (Wilson & King, 2003; Farrell, n.d.). The species is less typical of arable sites that V. triphyllos

and other CitM target species, relying on naturally stony ground and grazing to maintain sufficiently open

conditions (Farrell, n.d.).


None known.

1.6 Threats

Threats to Veronica verna are not described in detail, although the species has never been common in the

UK and has further declined as suitable habitat has been lost to agricultural intensification (Wilson & King,

2003).


2 Seed ecology

2.1 Seed longevity

The longevity of V. verna seed in the soil seed bank has not been established experimentally, although the

seed is believed to be long lived (Farrell, n.d.).




Under optimal ex situ storage conditions V. verna seed are long-lived – two UK collections held in the MSB

have retained 100% viability after 36 years under storage conditions of 15% eRH (equilibrium relative

humidity) and -20°C.


The MSB holds germination data for four UK collections of V. verna (Table 1). These tests consistently show

that V. verna will readily germinate across a range of constant and alternating temperatures typical of spring

and autumn in the UK. Germination begins quickly, with total germination after two weeks of incubation.

No dormany-breaking pre-treatments were applied, and neither warm nor cold stratification increased

germination percentage or germination rate.

Seed origin Collection

date Germination >85%

Germination <85%

Suffolk, England 23/07/77

2°C 20°C 25°C 20/10°C 25°C 4wks > 10°C

Suffolk, England 03/06/76 20/10°C

Suffolk, England 01/06/76 20/10°C 25/10°C

Suffolk, England 1974

15°C 20°C 25°C 25/10°C 2°C 4wks > 20°C

3 Propagation

RBG Kew has not attempted to grow V. triphyllos plants to maturity.

Table 1 MSB germination data for UK collections of V. verna.




Veronica verna is believed to be long-lived in the soil seed bank and may return with the reinstatement of

management practices that provide adequate germination and establishment niches. If the species has not

been recorded recently or has failed to return under a favourable management regime, reintroduction is

likely to be required.

Seed may be sown in autumn or spring – although most germination occurs in spring, sowing in autumn

mimics natural seed dispersal and provides an opportunity for autumn germination in wetter years. Seed

which does not germinate in autumn may remain quiescent in the soil and germinate in spring. Seed should

be sown onto disturbed ground with substantial areas of bare soil.

4.1 Sowing rate


Veronica verna does not display complex seed dormancy and a high proportion of viable seed exposed to

suitable germination conditions (moist soil, high light availability and moderate temperatures) may

germinate. Seedling establishment may be low, however, as the small seeds and seedlings are likely to be

vulnerable to disturbance, disease and herbivory, consistent with generally higher seedling mortality rates

in small-seeded species (Moles and Westoby, 2014). This would justify sowing at the higher rate

recommended by Lang et al. (2016) - preferably higher where sufficient seed is available.

1g of V. verna seed contains approximately 8,333 individual seeds.


Veronica verna is likely to benefit from management regimes that:

• ensure plants are able to complete their life cycle and disperse seed into the soil seed bank;

• maintain a short, open vegetation structure with areas of bare, disturbed ground.

It is essential that sites managed for V. verna are maintained as open habitats (JNCC, 2010), with relatively

intensive grazing by sheep or rabbits (Farrell, n.d.). Concentrating grazing when V. verna is not in active

growth - between July and March – may help reduce damage to plants. Routine cultivation is not desirable

(Farrell, n.d), although small-scale manual disturbances in autumn or spring may help create germination

niches in densely-vegetated sites.


5 References




Farrell, L, no date. Veronica verna species account, Online Atlas of the British and Irish Flora. Available:

https://www.brc.ac.uk/plantatlas/plant/veronica-verna.

JNCC, 2010. Species pages for 2007 UK BAP Priority Species: Veronica verna. Available:





Ecology, 92, pp. 372-383.

Scalone, R., Kolf, M., Albach, D., 2013. Mating system variation in Veronica (Plantaginaceae): inferences

from pollen/ovule ratios and other reproductive traits. Nordic Journal of Botany, 31, 372-384.



102.


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